Embodiments of the present disclosure relate to a low temperature poly-silicon thin film transistor (LTPS-TFT) array substrate and a manufacturing method thereof.
Applications of amorphous silicon (a-Si) are limited due to a number of defects or shortcomings. For example, such defects or shortcoming in a-Si TFT may cause lower turn-on (ON) current, lower mobility and lower stability. In order to overcome the defects or shortcomings of a-Si and enlarge the application field, more and more attentions have been paid to low temperature poly-silicon (LTPS) recently.
FIG. 1 is a structural schematic view showing a conventional LTPS-TFT array substrate. As shown in FIG. 1, the LTPS-TFT array substrate comprises: a base substrate 1 and a buffer layer 2, an active layer 3, a gate insulating layer 4, a gate electrode 5, a first insulating layer 6, source and drain electrodes 7, a second insulating layer 8, a pixel electrode 9 and a protection layer 10 formed on the base substrate. In order to manufacture this LTPS-TFT array substrate, the following seven patterning processes are performed by using seven masks for photolithography.
1. Forming the pattern of the active layer 3 by a first patterning process with a first mask;
2. Forming the pattern of the gate electrode 5 by a second patterning process with a second mask;
3. Forming via holes for connecting the source and drain electrodes 7 with the active layer 3 by a third patterning process with a third mask;
4. Forming the pattern of the source and drain electrodes 7 by a fourth patterning process with a fourth mask;
5. Forming a connection via hole for connecting the pixel electrode 9 with one of the source and drain electrodes by a fifth patterning process with a fifth mask;
6. Forming the pattern of the pixel electrode 9 by a sixth patterning process with a sixth mask; and
7. Forming the protection layer 10 by a seventh patterning process with a seventh mask, wherein the protection layer 10 may be formed of resin for example and used as a planarization layer in the case where an organic light emitting diode (OLED) is provided on the array substrate.
It can be seen that the manufacturing process of the conventional LTPS-TFT array substrate is complicated and the manufacture cost thereof is high. Thus, it is still difficult for the LTPS-TFT products to compete with the a-Si TFT products.